An example of article transport facilities that are currently used is a facility including a holding portion that holds a transport object, a movement operation portion that moves the holding portion, and a transport control portion that controls the operation of the movement operation portion and the holding portion so as to transport the transport object to a transport target location. Also, an inspection unit is used in such an article transport facility. Conventional examples of the article transport facility and the inspection unit are described in JP 2005-170544A.
The article transport facility of JP 2005-170544A is configured to move a holding portion holding an article to a transport position and transfer an article to a transfer target location.
In the article transport facility of JP 2005-170544A, an inspecting position is set at a position that is spaced directly above the transport position by a set amount. In the article transport facility, the holding portion holding the inspection unit is moved to an inspecting position, and thereafter the horizontal position of a detection target portion provided at an inspection target location is detected by a detection device provided in the inspection unit. Then, an offset amount measurement portion measures a horizontal offset amount between the transport target location and the holding portion positioned at the inspecting position based on detection information from the detection device, and a position update portion updates the transport position based on a measurement result obtained by the offset amount measurement portion.
In this way, the article transport facility of JP 2005-170544A is configured to move the holding portion to the inspecting position, detect the position of the detection target portion provided at the transport target location from the inspection unit held by the holding portion, and measure the horizontal offset amount between the transport target location and the holding portion.
However, for the article transport facility and the inspection unit of JP 2005-170544A, it is necessary to provide the detection target portion at the transport target location. For this reason, when it is difficult to always provide the detection target portion at the transport target location, the operator needs to install the detection target portion at the transport target location at the time of measuring the offset amount by the inspection unit. When there are many transport target locations, the operator needs to provide the detection target portion at each of the transport target locations. This has lead to a reduction in the efficiency of the operation for measuring the horizontal offset amount of the holding portion relative to the transport target location in a state in which the holding portion is positioned at an inspecting position.